The United Nations late on Monday removed the Saudi-led coalition fighting in Yemen from a blacklist of child rights violators after Riyadh angrily protested the decision.

Saudi Arabia had demanded that a UN report be "corrected" after it concluded that the coalition was behind the killing of more than 470 children - some 60 percent of all war child deaths since the conflict escalated last year.

UN Secretary-General Ban Ki-moon agreed to a Saudi proposal to review the facts and cases cited in the report jointly with the coalition, his spokesman Stephan Dujarric said.

"Pending the conclusions of the joint review, the secretary-general removes the listing of the coalition in the report's annex," he said.

Saudi Ambassador Abdullah al-Mouallimi told reporters that the coalition felt "vindicated," declaring that the removal of the coalition from the list was "final and unconditional".

The ambassador had earlier said he was "deeply disappointed" by the report, describing the number of child deaths blamed on the coalition as "wildly exaggerated."

However, Human Rights Watch charged that Ban had capitulated to Saudi pressure, noting that the United Nations itself had extensively documented the coalition's airstrikes on schools and hospitals in Yemen.

"After giving a similar pass to Israel last year, the UN Secretary-General’s office has hit a new low by capitulating to Saudi Arabia’s brazen pressure," said Philippe Bolopion, deputy director for global advocacy at Human Rights Watch, according to Reuters.

"Yemen’s children deserve better."

The reversal came just hours after the warring parties pledged to free all child prisoners although they failed to reach agreement on a wider release for the Muslim holy month of Ramadan.

"In the prisoners committee, an agreement was made on the unconditional release of children," Ismail Ould Cheikh Ahmed said in a statement.

There was no immediate word on how many children are held prisoner by the Saudi-backed government or by Houthi rebels and their allies.

The coalition launched an air campaign in support of Yemen's President Abedrabbo Mansour in March 2015 to push back Houthi rebels after they seized the capital Sanaa and many parts of the country.

The war has left some 6,400 people dead, with more than 80 percent of the population in desperate need of humanitarian aid, according to the UN.

The report was released on Thursday as the United Nations sought progress in talks held in Kuwait to try to end the war, with the two sides talking for weeks but thus far seemingly to little avail.

In the report, Ban blamed both sides for the killing but said that "grave violations against children increased dramatically as a result of the escalating conflict".

Mouallimi, however, warned that adding the coalition to the UN blacklist would be "counterproductive for the purposes of the peace negotiations on Yemen."

Saudi Arabia's permanent representative to the United Nations Abdallah Al-Mouallimi speaks at the UN headquarters in New York (AFP)

The ambassador acknowledged that "there were some collateral damages from time to time" but that the coalition had played a "positive role" in restoring Yemen's legitimate government and providing humanitarian aid.

Dujarric earlier defended the report, saying some adjustments would be made even though the list would remain intact.

But just a few hours later, the spokesman issued a statement announcing that the coalition would be removed from the list pending the review.

"I don't think it's a reversal of policy," Dujarric told reporters. "We will see what the review is and we will adjust the list as needed."

Human rights groups have repeatedly raised concerns about the heavy civilian toll from the Saudi-led campaign.